Micralestes acutidens is most similar to M. elongatus, from which it differs in the presence of multicuspid (vs. conical, monocuspid) inner dentary teeth, inner premaxillary and outer dentary teeth with greater number of cusps, and a slightly more robust body. Paugy (1990:80) has questioned the reported occurrence of this species in Nilo-Sudanic and West African drainages and, on the basis of the presence of conical inner dentary teeth, instead regards the form in these regions as M. elongatus. He does not, however, question the diagnostic utility of mono- versus multicuspid inner dentary teeth for differentiating these two species. Such a determination must await a thorough revisionary study and detailed comparison of the material from the Niger and Cross basins, the region of putative sympatry of these species. The population close to the source of the Zambezi is morphologically distinct, being larger and less deep than fish elsewhere in its range. The fish have red fins compared to the colourless or creamy fins of those elsewhere. This requires taxonomic investigation (Tweddle et al. 2004).

Justification:
This species has a wide distribution, with no known major widespread threats. It is therefore listed as Least Concern. It has also been assessed regionally as Least Concern for central, eastern, north eastern and southern Africa. The species used to be known (and caught) from Luxor and Aswan region of Egypt in the Nile. The impacts of the Aswan High Dam and pollution are thought to have caused this extirpation, and it is now assessed as Regionally Extinct within north Africa. There is no immigration of individuals from outside the region (above the High Dam).

This is a widespread species, found from Sudan to South Africa, and westerly as far as east Nigeria.

Central Africa:Micralestes acutidens is known from throughout the Congo River basin, including Lakes Kariba and Tanganyika. In Lower Guinea it is found in the Cross and Sanaga Rivers.

Eastern Africa: It is present in the Lower Shire (Tweddle and Willoughby 1979) and Rovuma Rivers.

Northern Africa: It used in to be found and caught from Luxor and Aswan in Egyptian Nile, but is now extirpated from the region.

Northeast Africa: This species is present in the Ghazal el Jebel systems, White Nile.

Southern Africa: It is known from Congo and Zambezi systems, including the Cunene and Okavango, and east coast rivers south to the Phongolo (Skelton 2001). This species is the only characin found in the northern tributaries of the upper Zambezi system in Zambia (Tweddleet al. 2004).

Micralestes acutidens is a pelagic, potamodromous species. It forms shoals in clear, flowing or standing, open water. Common in water with fringing vegetation. It appears to co-exist with the tigerfish Hydrocynus forskalii in open water although it is heavily preyed upon by that predator, particularly those shoals of tigerfish ranging up to 45 cm in length (Bell-Cross and Minshull 1988). Omnivorous, often feeding from surface waters on winged insects. Also takes insect larvae, crustaceans and eggs and fry of other fish (Bell-Cross and Minshull 1988). They mature after a year. A partial spawner of moderate fecundity, with usually fewer than 700 eggs per female. Shoals migrate upstream after first summer rains; breeds throughout the summer months. Used as forage fish and as bait for tigerfish and pike (Skelton 1993).